Method and composition of a hydrophilic polymer dispersion containing an inorganic flocculant to be used for the treatment of waste water

ABSTRACT

The present invention relates to the method and composition of a hydrophilic polymer dispersion containing an inorganic flocculent to be used for the treatment of waste water. More particularly, it relates to the method and composition of a hydrophilic polymer dispersion containing an inorganic flocculent, which has the properties of declining and reducing the water content of flock as well as water content of sludge cake obtained after treating the waste water.

TECHNICAL FIELD

The present invention relates to the method and composition of ahydrophilic polymer dispersion containing an inorganic flocculant to beused for the treatment of waste water. More particularly, it relates tothe method and composition of a hydrophilic polymer dispersioncontaining an inorganic flocculant, which has the properties ofdeclining and reducing the water content of flock as well as watercontent of sludge cake obtained after treating the waste water.

BACKGROUND ART

It has been recognized that the reduction of water content of sludgecake in the waste water is an important technical matter for protectingthe environmental contamination. Especially, the reduction of industrialwaste and waste water sludge becomes an important matter for theenvironment. The reduction of sludge has an advantage of the efficientdevelopment of land by minimizing the waste treatment space.

To minimize the content of water in the sludge, the method using thermalenergy has been used. However, it has a lot of drawbacks to require highenergy together with high operation cost. Accordingly, the use offlocculant to treat the waste water has been considered as an efficientmethod for treating the waste water.

The method of flocculation using a flocculant can be explained byfollowing mechanism. Firstly, colloidal particles are enhanced to becoagulated by the addition of inorganic flocculant in the waste water;secondly, the coagulated particles become larged by the influence offlocculant; lastly, the flocculated particles are separated by thedifference of sedimental velocity or floating velocity in the wastewater.

In the waste water having metal hydroxide, the anionic flocculant isdesirable, whereas the cationic flocculant is desirable in the wastewater having sulfur compound or clay. Further, the anionic flocculant iseffective for treating the water in the neutral waste water.

Recently, the technology using polymer flocculant has been developed.The polymer flocculant used for the treatment of colloidal materials inwaste water is high molecular weight compound, and it neutralizes andcollects the suspended particles. Further, the polymer flocculant isclassified into following groups: i) anionic polymer flocculant, suchas, sodium alginate, sodium polyacrylate, salt of maleic acid copolymer,partly hydrolyzed salt of polyacrylamide, ii) cationic polymerflocculent, such as, acrylate, methacrylate, hydrophilic aniline resinhydrochloride salt, polythiourea hydrochloride salt, polyethylene aminotriazole, polyvinyl benzyl trimethyl ammonium fluoride, chitosan,polyethylene amine, vinylpyridine copolymer, and iii) nonionic polymerflocculent, such as, starch, hydrophilic urea resin, polyacrylamide,polyoxyethylene.

Generally, it has been reported that the polymer flocculant forms theflock induced by bridging between colloid particle and polymerflocculant according to the force between them. The commerciallymarketed polymer flocculant has molecular weight in the range of10,000˜10,000,000.

The commercially marketed product contains the polymer or copolymer ofquaternary acrylate, dimethyl diallyl ammonium chloride, tertiaryacrylate and acrylamide.

The flocculation by the polymer flocculant depends upon the degree oflinear polymerization of the polymer flocculant, that is, molecularweight and ionic density. Further, the degree of polymerization iscontrolled by condition of polymerization, whereas the ionic density iscontrolled by molar ratio of cationic monomer.

Generally, the polymer flocculant having high degree of polymerizationmakes a large flock, and the polymer flocculant having strong ionicdensity raises a strength of flock. Also, there is a correlation betweendegree of polymerization and ionic density, so that the higher molecularweight of polymer flocculant becomes, and the lower ionic density ofpolymer flocculant becomes.

The flock formed by single injection of the polymer flocculant containsa large amount of water. Therefore, it requires additional steps forlowering water content of the flock. However, it has some limitation forfully drying the flock, because the flock has hygroscopic property initself.

The water content of the flock can influence the water content ofdehydrated sludge cake, which is removed and reclaimed. The smallerwater content of the sludge cake induces the smaller amount of cake,which causes the efficient treatment of the sludge. Further, suchsmaller cake sludge saves the cost for removing and reclaiming it.

The aqueous dispersions of water-soluble nonionic and anionicallycharged vinyl and allyl addition polymers were disclosed in WO 97/34933.Also, they can be obtained by polymerizing in the presence of ananionically charged water-soluble polymer stabilizer in a saturated saltsolution.

Further, the polymerization process of preparing a water-soluble polymerin the form of a water-continuous dispersion was described in EuropeanPat. 0 630,909 A1. In this process, the peak in-production viscositydeveloped in the aqueous reaction mixture is lower than the peakin-production viscosity developed in an equivalent batch polymerization.

For forming dialkylaminoalkyl (meth)acrylamide polymer dispersions, anovel dispersant system was disclosed in U.S. Pat. No. 5,597,859.Further, European Pat. 0 839,767 A2 suggested a method for clarifyingink-laden water obtained from the recycling of paper stocks by treatingsaid water with a conventional coagulant followed by treatment with ahydrophilic dispersion polymer. In this method, the hydrophilicdispersion flocculant is a copolymer of DMAEA·MCQ [dimethylaminoethyl(meth)acrylate methyl chloride quaternary] and (meth)acrylamide.

The improved process for the preparation of water soluble polymerdispersion was disclosed in European Pat. 0 657,478 A2.

However, none of prior references discloses the far enhanced waste watertreatment activity compared to formerly developed hydrophilic polymerdispersion.

DISCLOSURE OF INVENTION

The present invention relates to a hydrophilic polymer dispersioncomposition containing an inorganic flocculant and a method forpreparing such composition which comprises the following steps of: i)mixing acrylamide, cationic monomer, anionic monomer, polymer ofcationic monomer, anionic salt and inorganic flocculant, ii)1st-polymerizing the mixture obtained in previous step, iii)2nd-polymerizing the 1st-polymerized mixture containing unreactedmonomers completely, and iv) adding and mixing anionic salt to obtainedpolymers.

Further, the hydrophilic polymer dispersion containing an inorganicflocculent of the present invention is prepared by following steps of: i) mixing 1.0˜25 wt % of acrylamide, 0˜2 wt % of anionic monomer selectedfrom the group consisting of acrylic acid, methacrylic acid and itaconicacid, 1.0˜30 wt % of cationic monomer mixture of compound of formula Iand formula II, 0.5˜5 wt % of polymer selected from the group consistingof homopolymer of compound of formula I, homopolymer of compound offormula II and copolymer of compound of formula I and formula II, 10˜30wt % of anionic salt, 1˜10 wt % of inorganic flocculant, 0.01˜1 wt % ofnonionic surfactant, 0.05˜2 wt % of dispersion stabilizer and 40˜75 wt %of water;

ii) 1st-polymerizing the mixture in addition to 0.001˜0.1 wt % ofpolymerization initiator to said mixture;

iii) 2nd-polymerizing the 1st-polymerized mixture containing unreactedmonomers completely ; and

iv) adding and mixing 10˜30 wt % of anionic salt to obtained polymers.

 wherein

R₁ is hydrogen atom or methyl

R₂ and R₃ are each independently alkyl group having 1 to 3 carbon atoms

A₁ is oxygen atom or NH;

B₁ is alkylene group having 2 to 4 carbon atoms or hydroxypropylene; and

X₁ is anionic counter ion.

 wherein

R₄ is hydrogen atom or methyl

R₅ and R₆ are each independently alkyl group having 1 to 2 carbon atoms

R₇ is hydrogen atom or alkyl group having 1 to 2 carbon atoms

A₂ is oxygen atom or NH;

B₂ is alkylene group having 2 to 4 carbon atoms or hydroxypropylene ;and

X₂ is anionic counter ion.

BEST MODE FOR CARRYING OUT THE INVENTION

The conventional hydrophilic polymer flocculant contains a dispersion ofpolymer of mixture of cationic monomers and anionic monomers, whereasthe hydrophilic polymer dispersion of the present invention containsfurther inorganic flocculant. Further, the present invention enhancesthe degree of polymerization of the polymer dispersion by adding andmixing nonionic surfactant to the mixture of cationic monomers.

Acrylamide can be used as monomer, and acrylic acid, methacrylic acid oritaconic acid can be used as anionic monomer.

The cationic monomer of formula I and cationic monomer of formula II canbe mixed in a ratio of 10:0 to 2:8.

The reacting materials for the polymer are a cationic monomer of formulaI, cationic monomer of formula II, and homopolymer of cationic monomerof formula I, homopolymer of cationic monomer of formula II, orcopolymer of cationic monomer of formula I and formula II as polymer inthe present invention. The higher content of the cationic monomerinduces the higher ionic density, which causes the improved strength offlock. The quantity of monomers and polymers can be determinedexperimentally in consideration of size and strength of flock inflocculation.

Said monomer is soluble in initial salt solution, but polymer materialis insoluble in initial salt solution. Therefore, the anionic salt hasthe function for preparing dispersion by dispersing polymer materials tofine particles. Said anionic salt is selected from the group consistingof ammonium sulfate, ammonium chloride, sodium sulfate, magnesiumsulfate, aluminium sulfate, ammonium hydrogenphosphate, sodiumhydrogenphosphate, and potassium hydrogenphosphate. Further, half ormore of said anionic salt can be added before polymerization reaction,and the remaining said anionic salt has to be added after polymerizationreaction. It is proved as the desirable preparation method for thestable polymer dispersion experimentally.

The inorganic flocculant firstly introduced in the present invention hasthe functions of improving the strength of flock and reducing the watercontent of sludge cake. The dehydrating function of inorganic flocculantpromotes the patch flocculation of flock, which raises density of flockand reduces the water content of flock. Said inorganic flocculant isselected from the group consisting of polyaluminium chloride, ferrouschloride, ferric chloride, ferrous sulfate, ferric sulfate, aluminiumchlorohydrate, and aluminasol. In case that the content of inorganicflocculant is less than 1 wt %, the reducing effect of water contentshall not be sufficient. On the other hand, in case that the content ofinorganic flocculant is more than 10 wt %, the stability of dispersionshall be declined by inhibiting the dispersed state of polymerflocculant.

Said polymer flocculant and inorganic flocculant can be stabilized bystabilizer, such as, nonionic surfactant and glycerin. The particles ofdispersed polymer material is stabilized by following mechanisms of: i)steric hindrance of said nonionic surfactant and ii) repulsion caused byhigh charge of the polymer material. In case that the content ofnonionic surfactant is less than 0.01 wt %, stability of dispersionobtained is lowered. Further, in case that the content of nonionicsurfactant is more than 1 wt %, wasted surfactant remains. Also, 0˜2 wt% of glycerin can be used as subsidiary dispersant. In case that thecontent of glycerin is more than 2 wt %, glycerin is wasted. Further,the nonionic surfactant of the present invention activates the nucleiformation, which results in the reduction of in-production viscosity andthe stabilization of polymer particles caused by the steric hindrance ofthe surfactant. Therefore, the nonionic surfactant has a role to enhancethe mobility of the final product.

The azobis initiator, which is a kind of radical initiator, can be usedfor polymerizing said cationic monomer of formula I and formula II andsaid anionic monomer. 0.001˜0.1 wt % of said polymerization initiatorcan be used. In case that the content of initiator is less than 0.001 wt%, there are some drawbacks of: i) not maintaining polymerizationreaction and ii) obtaining insoluble polymer material having high degreeof polymerization. On the other hand, in case that the content ofinitiator is more than 0.1 wt %, there are some drawbacks of: i)increasing and generating the heat during the polymerization, ii)decreasing the yield of polymer material, and iii) preparing polymermaterial having low degree of polymerization.

The viscosity and pH of said hydrophilic polymer dispersion containingan inorganic flocculent can be controlled less than 1,000 cps and morethan pH 3.0. It is desirous that the viscosity and ionic density of 1%aqueous solution of the hydrophilic polymer dispersion is more than 40cps and more than 1.0 meq. In case that the product is centrifuged to1,800 rpm for 10 minutes, the precipitation has to be less than 5% oftotal weight in order to keep the product for a long time.

Further, the hydrophilic polymer dispersion containing an inorganicflocculant of the present invention is prepared by following steps of

[mixing step] i) mixing 1.0˜25 wt % of acrylamide, 0˜2 wt % of anionic

monomer, 1.0˜30 wt % of cationic monomer mixture of compound of

formula I and formula II, 0.5˜5 wt % of polymer selected from the groupconsisting of homopolymer of compound of formula I, homopolymer ofcompound of formula II and copolymer of compound of formula I andformula II, 10˜30 wt % of anionic salt, 1˜10 wt % of inorganicflocculant, 0.01˜1 wt % of nonionic surfactant, 0.05˜2 wt % ofdispersion stabilizer and 40˜75 wt % of water in the reactor, ii)nitrogen purging in the reactor, and agitating said mixture more than 30rpm;

[initiator adding step] i) heating said mixture at 30˜50° C., ii) adding0.00 1˜0.1 wt % of initiator to said mixture;

[1st-polymerizing step] 1st-polymerizing said mixture at 30˜50° C. for3˜6 hours;

[2nd-polymerizing step] 2nd-polymerizing the 1st-polymerized mixturecontaining unreacted monomers completely by adding 0.001˜0.1 wt % ofinitiator to said mixture for 3˜15 hours;

[finishing step] i) adding the remaining anionic salt to the polymer,ii) adjusting pH of the polymer less than 4.0, iii) sieving the polymerusing 40 ˜100 mesh.

In the mixing step, the inside of a reactor is purged with nitrogen, andthe raw materials are mixed and agitated homogeneously. Particularly, apart of anionic salt is added in this step, and the remaining part ofanionic salt is added after the polymerization. This mixing step isimportant for raising stability of the dispersion

In the initiator adding step, the initiator, for example, azobisinitiator or redox initiator, such as, ammonium persulfate and sodiumbisulfite is added for polymerizing anionic monomer, cationic monomer offormula I and II. Said mixture has to be heated at 30˜50° C. where thepolymerization is initiated. Further, in the 1st-polymerizing step, thereactor has to be cooled to achieve the maintenance of temperature at30˜50° C. This step has to be maintained for 3˜6 hours untilpolymerization is finished.

In the 2nd-polymerizing step, unreacted monomers in 1st-polymerizingstep is completely reacted to form the polymer in addition to saidinitiator at 30˜50° C. for 3˜15 hours. Therefore, the polymer dispersionis obtained.

The final product is obtained by the finishing step. In case that the pHof polymer dispersion is more than 4.0, the stability of dispersion islowered and the efficiency of dispersion is declined.

The present invention can be more specifically explained by thefollowing examples. However, it should be understood that the examplesare intended to illustrate, but not to limit the scope of the presentinvention in any manner.

EXAMPLE 1 Preparation of the Polymer Dispersion

The polymer dispersion is prepared by following steps of:i) mixing138.941 g of 50% acrylamide aqueous solution, 126.761 g ofdimethylaminoethyl acrylate benzyl chloride quaternary monomer (80%),36.401 g of dimethylaminoethyl acrylate methyl chloride quaternarymonomer (80%), 20.0 g of dimethylaminoethyl acrylate methyl chloridequaternary polymer (20%), 5.0 g of dimethyldiallyl ammonium chloridepolymer (40%), 131.707 g of ammonium sulfate, 2.0 g of aromaticethoxylate, 6.0 g of glycerin, 160.0 g of polyaluminium chloride (10%)and 304.897 g of water in the 5-neck flask, ii) nitrogen purging in thereactor, and agitating said mixture to 200 rpm, iii) heating saidmixture at 46° C., iv) adding 0.04 g of azobis initiator (V-50) to saidmixture, v) 1st-polymerizing said mixture at 46° C. for 3˜6 hours, vi)2nd-polymerizing the 1st-polymerized mixture containing unreactedmonomers completely by adding 0.04 g of said initiator (V-50) to saidmixture for 3˜15 hours, vii) adding 68.293 g of ammonium sulfate to thepolymer, vi) adjusting pH of the polymer to 4.0, ix) sieving the polymerusing 60 mesh.

EXAMPLE 2 Preparation of the Polymer Dispersion

The polymer dispersion is prepared by following steps of i) mixing190.211 g of 50% acrylamide aqueous solution, 102.270 g ofdimethylaminoethyl acrylate benzyl chloride quaternary monomer (80%),38.463 g of dimethyldiallyl ammonium chloride monomer (60%), 10.0 g ofdimethylaminoethyl acrylate methyl chloride quaternary polymer (20%),10.0 g of dimethyldiallyl ammonium chloride polymer (40%), 122.201 g ofammonium sulfate, 2.0 g of aromatic ethoxylate, 10.0 g of glycerin,100.0 g of ferric sulfate (8%) and 337.055 g of water in the 5-neckflask, ii) nitrogen purging in the reactor, and agitating said mixtureto 200 rpm, iii) heating said mixture at 37° C., iv) adding 0.05 g ofazobis initiator (VA-044) to said mixture, v) 1st-polymerizing saidmixture at 37° C. for 3˜6 hours, vi) 2nd-polymerizing the1st-polymerized mixture containing unreacted monomers completely byadding 0.05 g of said initiator (VA-044) to said mixture for 3˜15 hours,vii) adding 77.108 g of ammonium chloride to the polymer, viii)adjusting pH of the polymer to 4.0, ix) sieving the polymer using 60mesh.

EXAMPLE 3 Preparation of the Polymer Dispersion

The polymer dispersion is prepared by following steps of: i) mixing34305 g of 50% acrylamide aqueous solution, 203,432 g ofdimethylaminoethyl acrylate benzyl chloride quaternary monomer (80%),87.627 g of dimethylaminoethyl acrylate methyl chloride quaternarymonomer (80%), 18.75 g of dimethylaminoethyl acrylate methyl chloridequaternary polymer (20%), 15.625 g of dimethyldiallyl ammonium chloridepolymer (40%), 116.747 g of ammonium sulfate, 2.0 g of aromaticethoxylate, 125.0 g of aluminium chlorohydrate (10%) and 332.261 g ofwater in the 5-neck flask, ii) nitrogen purging in the reactor, andagitating said mixture to 200 rpm, iii) heating said mixture at 35° C.,iv) adding 0.05 g of azobis initiator (VA044) to said mixture, v)1st-polymerizing said mixture at 35° C. for 3˜6 hours, vi)2nd-polymerizing the 1st-polymerized mixture containing unreactedmonomers completely by adding 0.05 g of said initiator (VA-044) to saidmixture for 3˜15 hours, vii) adding 63.253 g of ammonium chloride to thepolymer, vii) adjusting pH of the polymer to 4.0, ix) sieving thepolymer using 60 mesh.

The polymer dispersions prepared in Example 1˜3 have less tan 2% ofwater content of flock as compared with conventional polymer dispersionsin dry test.

EXAMPLE 4 Test of Flocculation Effect

The hydrophilic polymer dispersion containing an inorganic flocculant ofthe present invention and the commercially marketed polymer dispersionsnot containing an inorganic flocculant, such as, i) powder flocculant(A), ii) emulsion flocculant (B), and iii) dispersion flocculant (C) areselected as tested flocculants. The flocculation effect is measured byusing the surplus sludge of manure waste water having pH 6.8 with 5,500ppm of solid concentration, and the result is shown in Table 1.

This test is carried out by following steps of: i) adding 500 ml ofsludge to each 500 ml beaker by using cylinder respectively, ii) addingeach amount of the flocculant to said sludge by using pipet, iii)agitating said mixture in 100 rpm, iv) stop agitating and measuring theflock size at the time of finishing flock growth, v) agitating saidmixture in 300 rpm for 10 seconds, vi) measuring the flock size,

TABLE 1 Suspended solid concentration water content Input amount Flocksize Flock strength after flocculation of sludge cake Flocculant (mg/l)(mm) (min)* (ppm) (%) Example 1 200 4˜5 2˜3 25 72 Example 2 200 4˜5 2˜320 71 Example 3 200 4˜5 2˜3 24 74 A 200 4˜5 1˜2 70 83 B 200 5˜6 1˜2 5086 C 200 4˜5 1˜2 65 84 *shows the size of the flock which is measuredafter vigorous stirring of the mixture.

Further, the flocculation effect is measured by using the dried sludgeof leather waste water having pH 7.2 with 18,000 ppm of solidconcentration, and the result is shown in Table 2.

TABLE 2 Suspended solid concentration water content Input amount Flocksize Flock strength after flocculation of sludge cake Flocculant (mg/l)(mm) (min) (ppm) (%) Example 1 500 5˜6 3˜4 35 70 Example 2 500 5˜6 3˜435 72 Example 3 500 5˜6 3˜4 40 75 A 500 6˜7 2˜3 90 86 B 500 7˜8 2˜3 8585 C 500 5˜6 2˜3 70 82

Further, the flocculation effect is measured by using the dried sludgeof food waste water having pH 7.5 with 8,000 ppm of solid concentration,and the result is shown in Table 3.

TABLE 3 Suspended solid concentration water content Input amount Flocksize Flock strength after flocculation of sludge cake Flocculant (mg/l)(mm) (min) (ppm) (%) Example 1 250 3˜4 2˜3 8 71 Example 2 250 3˜4 2˜3 1074 Example 3 250 3˜4 2˜3 12 73 A 250 3˜4 1˜2 25 83 B 250 4˜5 1˜2 20 81 C250 4˜5 1˜2 45 84

In this test, the hydrophilic polymer dispersion of the presentinvention induces equal flock size and improved flock strength ascompared with the commercially marketed polymer dispersions. Therefore,the hydrophilic polymer dispersion of the present invention has anexcellent effect for removing sludge by forming flock.

The hydrophilic polymer dispersion of the present invention may beuseful for the manufacture of paper to make an aqueous cellulosicsuspension or slurry. Hence, said hydrophilic polymer dispersion will beimportant for the efficient cost of papermaking manufacture.

What is claimed is:
 1. A hydrophilic polymer dispersion containing aninorganic flocculant prepared by following steps of: i ) mixing 1.0˜25wt % of acrylamide, 0˜2 wt % of anionic monomer selected from the groupconsisting of acrylic acid, methacrylic acid and itaconic acid, 1.0˜30wt % of cationic monomer mixture of compound of formula I and formulaII, 0.5 ˜5 wt % of polymer selected from the group consisting ofhomopolymer of compound of formula I, homopolymer of compound of formulaII and copolymer of compound of formula I and formula II, 10˜30 wt % ofanionic salt, 1˜10 wt % of inorganic flocculant, 0.01˜1 wt % of nonionicsurfactant, 0.05˜2 wt. % of dispersion stabilizer and 40˜75 wt % ofwater; ii) 1st-polymerizing the mixture with the addition of 0.001˜0.1wt % of polymerization initiator to said mixture; iii)2^(nd)-polymerizing the 1^(st)-polymerized mixture containing unreactedmonomers completely; and iv) adding and mixing 10˜30 wt % of anionicsalt to the obtained polymers.

 wherein R₁ is hydrogen atom or methyl; R₂ and R₃ are each independentlyalkyl group having 1 to 3 carbon atoms; A₁ is oxygen atom or NH; B₁ isalkylene group having 2 to 4 carbon atoms or hydroxypropylene; and X₁ isanionic counter ion.

 wherein R₄ is hydrogen atom or methyl; R₅ and R₆ are each independentlyalkyl group having 1 to 2 carbon atoms; R₇ is hydrogen atom or alkylgroup having 1 to 2 carbon atoms; A₂ is oxygen atom or NH; B₂ isalkylene group having 2 to 4 carbon atoms or hydroxypropylene; and X₂ isanionic counter ion.
 2. The hydrophilic polymer dispersion according toclaim 1, wherein said inorganic flocculant is selected from the groupconsisting of polyaluminium chloride, ferrous chloride, ferric chloride,ferrous sulfate, ferric sulfate, aluminium chlorohydrate, andaluminasol.
 3. The hydrophilic polymer dispersion according to claim 1,wherein said anionic salt is selected from the group consisting ofammonium sulfate, ammonium chloride, sodium sulfate, magnesium sulfate,aluminium sulfate, ammonium hydrogenphosphate, sodium hydrogenphosphate,and potassium hydrogenphosphate.
 4. The hydrophilic polymer dispersionaccording to claim 1, wherein said dispersion stabilizer is selectedfrom the group consisting of nonionic surfactant and glycerin.
 5. Thehydrophilic polymer dispersion according to claim 1, wherein the ratioof cationic monomer mixture of compound of formula I and formula II isin the range of 10:0 to 2:8.
 6. A process for preparing hydrophilicpolymer dispersion containing an inorganic flocculant comprising thesteps of: i) mixing 1.0˜25 wt % of acrylamide, 0˜2 wt % of anionicmonomer selected from the group consisting of acrylic acid, methacrylicacid and itaconic acid, 1.0˜30 wt % of cationic monomer mixture ofcompound of formula I and formula II, 0.5˜5 wt % of polymer selectedfrom the group consisting of homopolymer of compound of formula I,homopolymer of compound of formula II and copolymer of compound offormula I and formula II, 10˜30 wt % of anionic salt, 1˜10 wt % ofinorganic flocculant, 0.01˜1 wt % of nonionic surfactant, 0.05˜2 wt % ofdispersion stabilizer and 40˜75 wt % of water; ii) 1^(st)-polymerizingthe mixture with the addition of 0.001 ˜0.1 wt % of polymerizationinitiator to said mixture; iii) 2^(nd)-polymerizing the1^(st)-polymerized mixture containing unreacted monomers completely; andiv) adding and mixing 10˜30 wt % of anionic salt to the obtainedpolymers.

 wherein R₁ is hydrogen atom or methyl; R₂ and R₃ are each independentlyalkyl group having 1 to 3 carbon atoms; A₁ is oxygen atom or NH; B₁ isalkylene group having 2 to 4 carbon atoms or hydroxypropylene; and X₁ isanionic counter ion.

 wherein R₄ is hydrogen atom or methyl; R₅ and R₆ are each independentlyalkyl group having 1 to 2 carbon atoms; R₇ is hydrogen atom or alkylgroup having 1 to 2 carbon atoms; A₂ is oxygen atom or NH; B₂ isalkylene group having 2 to 4 carbon atoms or hydroxypropylene; and X₂ isanionic counter ion.
 7. The process for preparing hydrophilic polymerdispersion containing an inorganic flocculant according to claim 6,further comprising the steps of: i) mixing 1.0˜25 wt % of acrylamide,0˜2 wt % of anionic monomer, 1.0˜30 wt % of cationic monomer mixture ofcompound of formula I and formula II, 0.5˜5 wt % of polymer selectedfrom the group consisting of homopolymer of compound of formula I,homopolymer of compound of formula II and copolymer of compound offormula I and formula II, 10˜30 wt % of anionic salt, 1˜10 wt % ofinorganic flocculant, 0.01˜1 wt % of nonionic surfactant, 0.05˜2 wt % ofdispersion stabilizer and 40˜75 wt % of water in the reactor; ii)nitrogen purging in the reactor, and agitating said mixture more than 30rpm; iii) heating said mixture at 30˜50° C.; iv) adding 0.00˜0.1 wt % ofinitiator to said mixture; v) 1^(st)-polymerizing said mixture at 30˜50°C. for 3˜6 hours; vi) 2^(nd)-polymerizing the 1^(st)-polymerized mixturecontaining unreacted monomers completely by adding 0.001˜0.1 wt % ofinitiator to said mixture for 3˜15 hours; vii) adding the remaininganionic salt to the polymer; viii) adjusting the pH of the polymer toless than 4.0; and ix) sieving the polymer using 40˜100 mesh.
 8. Ahydrophilic polymer dispersion composition comprising: i) acrylamide,ii) an anionic monomer selected from the group consisting of acrylicacid, methacrylic acid, and itaconic acid, iii) a cationic monomermixture of a compound of formula (I) and formula (II), iv) a polymerselected from the group consisting of a homopolymer of a compound offormula (I), a homopolymer of a compound of formula (II) and a copolymerof a compound of formula (I) and formula (II), v) an anionic salt, vi)an inorganic flocculant, vii) a nonionic surfactant, viii) a dispersionstabilizer; ix) and water

 wherein R₁ is a hydrogen atom or methyl; R₂ and R₃ are eachindependently an alkyl group having 1 to 3 carbon atoms; A₁ is an oxygenatom or NH; B₁ is an alkylene group having 2 to 4 carbon atoms orhydroxypropylene; and X₁ is an anionic counter ion

 Wherein R₄ is a hydrogen atom or methyl; R₅ and R₆ are eachindependently an alkyl group having 1 to 2 carbon atoms; R₇ is ahydrogen atom or an alkyl group having 1 to 2 carbon atoms; A₂ is anoxygen atom or NH; B₂ is an alkylene group having 2 to 4 carbon atoms orhydroxypropylene; and X₂ is an anionic counter ion.
 9. The hydrophilicpolymer composition according to claim 8, wherein the inorganicflocculant is selected from the group consisting of polyaluminumchloride, ferrous chloride, ferric chloride, ferrous sulfate, ferricsulfate, aluminum chlorohydrate and aluminasol.
 10. The hydrophilicpolymer composition according to claim 8, wherein the anionic salt isselected from the group consisting of ammonium sulfate, ammoniumchloride, sodium sulfate, magnesium sulfate, aluminum sulfate, ammoniumhydrogen phosphate, sodium hydrogen phosphate and potassium hydrogenphosphate.
 11. The hydrophilic polymer dispersion composition accordingto claim 8, wherein the dispersion stabilizer is selected from the groupconsisting of a nonionic surfactant and glycerin.
 12. The hydrophilicpolymer dispersion composition according to claim 8, wherein the ratioof the cationic monomer mixture of the compound of formula (I) andformula (II) is in the range of 10:0 to 2:8.